After much searching and trial and error I was finally able to programming the central locking buttons on a new key!  I couldn't find the exact instructions anywhere but this hybrid, of the ones that I did find, worked for me.  (NB: After I did this I swapped the blade and transponder into the new key from the spare key - the one that doesn't have buttons). NB: Complete the following in under 2 minutes 1- Ensure Ignition is in the OFF position 2- Open Driver’s door 3- Switch